Conventionally, polymer compositions are widely used for domestic articles and industrial goods as plastic or rubber materials. The color tone of these types of polymer compositions is considered to be one of the important quality items of polymer compositions as it may possibly affect the quality of the final products. Factors for deterioration of color tone of polymer compositions include, for example, discoloration caused by heating or heat generation due to shearing stress during the working process of polymer compositions, as well as discoloration due to storage condition of products from polymer composition materials. The polymer composition comprises a phenol compound as a stabilizer in order to improve the problem of color tone. Such a polymer composition is produced, for example, by the method described in Patent Document 1.
Recently, polymerization conditions in the production of polymers has become severe, accompanied by improvement in the productivity of polymers. For example, polymerizing a monomer by a high temperature polymerization enables the productivity for the polymer to improve. Polymers, however, have a tendency to discolor in polymerization under severe conditions; thus there has been a problem that such discoloration could not be effectively inhibited by only a phenol compound.    [Patent Document 1]: Japanese Laid-Open Patent Publication No. 8-59733